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Transcript

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0:00

Hello.Today's talk is on the
Genome-wide Organizationof Chromatin and the
Transcriptional Machinery.My name is Dr. Frank Pugh.I'm from the Center for Eukaryotic
Gene Regulation at Penn StateUniversity in State
College, Pennsylvania.As a way of background, I've
got my undergraduate degreeat Cornell University in
Ithaca, New York in 1983and then went on to graduate
school in biochemistryat the University of
Wisconsin at Madison,working on genetic recombination.I got my Ph.D. in 1987.I then went on to the
University of Californiaat Berkeley where I studied under
Dr. Robert Teigen for a postdocAfter which in 1991, I started my
own lab at Penn State Universityand have been there ever since.And the focus of my research has
been on biochemical and genomicmechanisms of eukaryotic
gene regulation.

0:56

Shown here is an image of
a typical eukaryotic geneand the proteins that bind to it.The green balls that you
see are the nucleosomeswhich package the chromatin.And you can see by that
small black arrow, the TSS,is where the transcriptional
start site resides.Between the minus 1 and
the plus 1 nucleosomesis an open region where
there are no nucleosomes.And that is where the
transcription machinery assembles.And there is, perhaps, four stages
that you can think of assembly.One is orchestration.That's those red circles
that bind to specific DNAsequences at or near
the minus 1 nucleosome.The second step involves,
perhaps, chromatin remodeling,the rearrangement of
proteins on the DNA surfaceto make the DNA more accessible to
other transcription factor binding.So that's step two, access.The third step is the assembly
of the general transcriptionalmachinery in the initiation phase.That's shown in light
blue at the promoternucleosome-free region.And then, that's
followed in step fourby the recruitment of RNA
polymerase in elongation factorsthat ultimately need
to enter into the geneand transcribe the genome.We're going to first talk
about the organizationof nucleosomes shown here.